I believe that I'm having a problem with the OpenWRT and tftp.

I'm trying to fetch a file outside of the OpenWRT firewall using tftp but on the server side I see these messages:

in.tftpd[26104]: tftpd: read(ack): Connection refused

The client just times out.

I suspect its a nat issue with the OpenWRT perhaps related to the fact the OpenWRT listens on a tftp port for uploads of firmware?

Or is tftp generally tricky through nat? I can't see why it would be.

Is there some kind of iptables parameter that needs to be added? Scant little comes up on google for iptables, nat and tftp.